Direct Numerical Simulation of Passive Scalar Mixing in Axisymmetric Swirling Jets

Direct Numerical Simulation (DNS) of transport of multiple passive scalars with varying molecular diffusivity in a spatially evolving low-swirl axisymmetric swirling jet is performed at a Reynolds number of 1500. The swirling jets discussed are limited to non-vortex breakdown flow. Multiple passive scalars with differing molecular diffusivity are introduced into the jet and allowed to evolve with the flow field. The DNS result reveals that the scalar decay varies with the jet swirl number as well as the Schmidt number corresponding to the scalar. Furthermore, the scalar decay exhibits non-linearity.